US FDA approves Alexion's rare blood disease drug

(Reuters) - U.S. health regulators cleared on Friday an Alexion Pharmaceuticals drug for adults and children with a very rare genetic disorder, as the company expands the uses of its flagship medicine.

The Food and Drug Administration approved Soliris for children and adults with atypical hemolytic uremic syndrome (aHUS), a life-threatening genetic disease that damages vital organs and can lead to stroke, heart attack or kidney failure.

Soliris, generically known as eculizumab, is the first approved treatment for atypical HUS, one type of the rare disease that disproportionately affects children.

The drug is a targeted therapy that works by inhibiting chronic and uncontrolled activation of proteins that cause blood clots and organ damage in patients with aHUS.

Cheshire, Connecticut-based Alexion derives all its revenue from the medicine that in 2007 received FDA approval for treating a serious and also rare blood disorder called paroxysmal nocturnal hemoglobinuria, which can lead to disability and premature death.

The company has forecast revenue of $745 million to $755 million in 2011 and said it is testing Soliris in nine other indications, with results expected by the end of the year.

The U.S. label for Soliris includes a boxed warning of life-threatening and fatal meningococcal infections occurring in patients treated with the medication, Alexion said. The drug's most common side-effects include high blood pressure, diarrhea, anemia, vomiting, nausea, a decrease in white blood cells and upper respiratory and urinary tract infections.

Current standard treatment of aHUS is plasma therapy, the safety and effectiveness of which has not been assessed in well-controlled studies, the FDA said. Even with that treatment, currently more than half of all patients with aHUS die, require kidney dialysis or have permanent kidney damage within a year of diagnosis, Alexion said.

The European Commission is expected to decide on extending approval for Soliris to pediatric and adult patients with aHUS in about two months, the company said.